In general, phenol is manufactured by oxidizing cumene to form cumene hydroperoxide. The cumene hydroperoxide is cleaved to produce phenol and acetone. If s-butylbenzene (SBB) is used as a feed in place of or in addition to cumene, the process produces the generally higher value ketone, methyl ethyl ketone (MEK), either alone or in combination with acetone. The process also produces acetophenone. Often, the acetophenone is discarded as waste.
JP 2004331532: A: 2004112: 5 D W2004-8 describes a method for producing refined AP from crude AP during the production of phenol from cumene. The crude AP is produced by thermally decomposing bottom liquid remaining after separation of phenol from crude phenol. The crude AP is introduced into a distillation tower which is decompressed to a bottom pressure of 13.33 kPa or below. In one embodiment, the bottom pressure is 6.6 kPa or below. The AP product is said to “satisf[y] quality requirement of acetophenone.”
Cleavage of SBB-hydroperoxide produces different intermediates than cleavage of cumene hydroperoxide. Thermal decomposition of a bottom liquid also would be expected to alter the composition of the bottom liquid, perhaps even forming unwanted byproducts.
Methods are needed to recover acetophenone during phenol production without thermally decomposing the target stream.